US5609975A - Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same - Google Patents

Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same Download PDF

Info

Publication number
US5609975A
US5609975A US08/439,218 US43921895A US5609975A US 5609975 A US5609975 A US 5609975A US 43921895 A US43921895 A US 43921895A US 5609975 A US5609975 A US 5609975A
Authority
US
United States
Prior art keywords
unit
copolymer
vinylidene fluoride
positive electrode
tetrafluoroethylene
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US08/439,218
Inventor
Masaki Hasegawa
Yasuhiko Bito
Shuji Ito
Toshihide Murata
Yoshinori Toyoguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BITO, YASUHIKO, HASEGAWA, MASAKI, ITO, SHUJI, MURATA, TOSHIHIDE, TOYOGUCHI, YOSHINORI
Application granted granted Critical
Publication of US5609975A publication Critical patent/US5609975A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H01M4/623—Binders being polymers fluorinated polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a positive electrode for non-aqueous electrolyte lithium secondary batteries and a method of manufacturing the same.
  • Non-aqueous electrolyte secondary batteries having a lithium or lithium compound negative electrode have been studied extensively for their potentials for high voltage and high energy density.
  • Positive electrode-active materials of non-aqueous electrolyte secondary batteries proposed hitherto include oxides of transition metals and chalcogen compounds, such as Li x CoO 2 , Li x Mn 2 O 4 , Li x FeO 2 , Li x NiO 2 , V 2 O 5 , Cr 2 O 5 , MnO 2 , TiS 2 , MoS 2 , and the like.
  • LiCoO 2 Li x CoO 2
  • LiNiO 2 Li x NiO 2
  • LiMnO 2 Li x MnO 2
  • LiMn 2 O 4 LiMn 2 O 4
  • LiCoO 2 is a most promising positive electrode active material because of its favorable properties.
  • LiNiO 2 While cobalt contained in LiCoO 2 is relatively expensive, LiNiO 2 , which is cheaper and thus allows stable supply, has been noted recently. LiNiO 2 has a similar composition and structure to those of LiCoO 2 and is expected to give a high capacity and a high voltage as a positive electrode active material for lithium secondary batteries. Improved synthesis has increased the capacity of LiNiO 2 to the level exceeding LiCoO 2 . LiMn 2 O 4 has also excellent properties with a slightly lower capacity, and LiMnO 2 has also been studied extensively for practical applications.
  • Binders generally applied for preparation of positive electrodes with these active materials are required to be chemically inactive and stable against organic electrolyte.
  • Polytetrafluoroethylene having a structural formula represented by the formula (1), which is a chemically inactive and stable resin, is widely used as the binder.
  • a typical method applied to preparation of electrodes includes the steps of mixing an aqueous dispersion of a resin powder with an active material, a conductive agent and other additives to prepare a paste, and applying the paste onto current collectors or electrically-conductive electrode supports to form electrodes.
  • Another method comprises mixing of a powdery binder with an active material, a conductive agent and other additives in dry stage and pressure-molds the mixture.
  • Electrodes containing LiNiO 2 as an active material have varying properties according to the types of a binder and a dispersion medium. This is partly ascribed to the high reactivity of LiNiO 2 with water. LiNiO 2 easily causes an ion exchange reaction between protons and lithium ions in the presence of water, thus lowering the capacity.
  • the former method using water as a dispersion medium undesirably lowers the capacity.
  • the present invention provides a positive electrode for a non-aqueous electrolyte lithium secondary battery, which comprises a positive electrode active material represented by the general formula Li x A 1-y M y O 2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, St, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05 ⁇ x ⁇ 1.1, and 0 ⁇ y ⁇ 0.5), a binder, a conductive agent and a current collector.
  • a positive electrode active material represented by the general formula Li x A 1-y M y O 2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, St, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu
  • the binder is at least one member selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.
  • the copolymer comprising a vinylidene fluoride unit is preferably selected from the group consisting of a copolymer comprising a vinylidene fluoride unit and a hexafluoropropylene unit; a copolymer comprising a vinylidene fluoride unit and a pentafluoropropylene unit; a copolymer comprising a vinylidene fluoride unit and a chlorotrifluoroethylene unit; a copolymer comprising a vinylidene fluoride unit, a hexafluoropropylene unit and a tetrafluoroethylene unit; a copolymer comprising a vinylidene fluoride unit, a pentafluoropropylene unit and a tetrafluoroethylene unit; and a copolymer comprising a vinylidene fluoride unit, a perfluoromethyl vinyl ether unit and a tetrafluoroethylene unit
  • the copolymer comprising a vinylidene fluoride unit is an elastomer (fluorocarbon rubber) and cross-linked in a resultant electrode.
  • the present invention is also directed to a method of manufacturing a positive electrode for a non-aqueous electrolyte lithium secondary battery.
  • the method comprises the steps of:
  • A represents at least one transition element selected from the group consisting of Mn, Co, and Ni
  • M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05 ⁇ x ⁇ 1.1, and 0 ⁇ y ⁇ 0.5
  • a binder a conductive agent and an organic solvent to prepare a paste
  • the binder is selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.
  • FIG. 1 is a longitudinal cross sectional view illustrating a secondary battery in an embodiment of the present invention.
  • Completion of the present invention is based on examination of various binders and dispersion media or solvents applied to preparation of an electrode with a positive electrode active material, especially LiNiO 2 . Since water contained in an aqueous dispersion of polytetrafluoroethylene deteriorates properties of the active material as described previously, a dispersion in an organic solvent has been examined.
  • An electrode was therefore prepared in a non-aqueous system using as a binder polyvinylidene fluoride, which is a fluorocarbon resin soluble in some organic solvents and has a structural formula represented by the formula (2).
  • a paste-like mixture was prepared by mixing polyvinylidene fluoride dissolved in an organic solvent with an active material and a conductive agent and applied onto a current collector to prepare an electrode plate.
  • Fluorocarbon resins and elastomers given below have been selected for a binder, which is less active to the organic electrolyte than vinylidene fluoride polymer and allows preparation of electrodes in a non-aqueous system. These binders enable preparation of high-performance positive electrodes of lithium secondary batteries.
  • Applicable fluorocarbon resins and elastomers include tetrafluoroethylene-hexafluoropropylene copolymers represented by the formula (3), vinylidene fluoride-hexafluoropropylene copolymers represented by the formula (4), vinylidene fluoride-pentafluoropropylene copolymers represented by the formula (5), vinylidene fluoride-chlorotrifluoroethylene copolymers represented by the formula (6), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers represented by the formula (7), vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymers represented by the formula (8), vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymers represented by the formula (9), tetrafluoroethylene-propylene copolymers represented by the formula (10
  • the vinylidene fluoride-chlorotrifluoroethylene copolymer contains from 50 to 75 mol % of the vinylidene fluoride unit, while the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer and vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer contain from 20 to 50 mol % of the vinylidene fluoride unit and not greater than 30 mol % of the tetrafluoroethylene unit.
  • the vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer contains from 10 to 50 mol % of the vinylidene fluoride unit and not greater than 35 mol % of the tetrafluoroethylene unit, while the tetrafluoroethylene-propylene copolymer contains from 30 to 60 mol % of the tetrafluoroethylene unit.
  • the tetrafluoroethylene-hexafluoropropylene copolymer is effectively dispersed in an organic solvent and allows preparation of electrodes in a non-aqueous system.
  • the tetrafluoroethylene-hexafluoropropylene copolymer is chemically stable as polytetrafluoroethylene and has excellent properties sufficient for a binder applied to positive electrodes of lithium secondary batteries.
  • the fluorocarbon elastomers are soluble in some organic solvents and allow preparation of electrodes in a non-aqueous system. Cross-linking reactions of the elastomers enhance the properties including solvent resistance and heat resistance and give electrodes having sufficient chemical stability. These elastomers also improve the cycle performance, which constitute a drawback of LiNiO 2 used as the positive electrode active material.
  • the fluorocarbon elastomers (fluorocarbon rubbers) applied as a binder have sufficient elasticity to effectively prevent destruction of active material particles and electrodes due to a variation in volume of an active material in the charge and discharge process, thereby improving the cycle performance.
  • the present invention is also preferably applicable to electrodes containing a compound, such as LiCoO 2 and LiMn 2 O 4 , as an active material.
  • a compound such as LiCoO 2 and LiMn 2 O 4
  • an aqueous dispersion of polytetrafluoroethylene is conventionally used for preparation of a paste-like mixture of active material. Remaining lithium salts in the active material in the course of synthesis thereof increase the pH level of the paste, which may corrode the current collector or cause other troubles in preparation of electrodes.
  • a possible countermeasure taken improves the conditions of synthesis of an active material to prevent contamination by nonreacted lithium salts, while another countermeasure washes an active material powder with water prior to preparation of electrodes to remove remaining lithium salts.
  • These countermeasures which are generally time- and labor-consuming, are, however, significantly affected by varied qualities of starting materials for synthesis of an active material and may not yield electrodes having excellent properties and stability.
  • the present invention is applicable to LiCoO 2 and LiMn 2 O 4 used as a positive electrode active material to yield stable and high-performance electrodes without being affected by the varying conditions of synthesis of an active material.
  • the present invention does not cause any troubles including corrosion of the current collector at the raised pH due to dissolution of remaining lithium salts.
  • the fluorocarbon elastomers fluorocarbon rubbers further improve the cycle performance of these compounds, like LiNiO 2 described above.
  • a positive electrode was prepared by utilizing LiNiO 2 as an active material and a dispersion of tetrafluoroethylene-hexafluoropropylene copolymer in an organic solvent as a binder.
  • FIG. 1 is a longitudinal cross sectional view illustrating a secondary battery having the positive electrode plate thus prepared.
  • a positive electrode 1 having a current collector 8 was arranged on the center of a casing 2.
  • a porous polypropylene film used as a separator 3 was disposed on the positive electrode 1.
  • a negative electrode 4 was a carbon electrode prepared by applying a paste-like mixture of carbon powder and styrene-butadiene rubber (SBR) latex in a weight ratio (solid content) of 100:2 onto a current collector 6 of copper foil.
  • SBR styrene-butadiene rubber
  • a non-aqueous electrolyte was prepared by dissolving 1 mol/l lithium hexafluorophosphate in a mixture of ethylene carbonate and diethyl carbonate (1:1 by volume).
  • the electrolyte was poured onto the separator 3 in the casing 2 and onto the negative electrode 4 incorporated in a sealing plate 7.
  • the sealing plate 7 with a gasket 5 and the casing 2 were then assembled to give a sealed battery. Since the negative electrode had a capacity sufficiently greater than that of the positive electrode, a capacity of the battery was restricted by the capacity of the positive electrode.
  • This battery is hereinafter referred to as battery A.
  • the charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V.
  • the condition of high-temperature storage was at 60° C. for 20 days under the charged condition of the second cycle.
  • Table 1 shows mean values of capacities immediately before the storage, voltages and capacity maintenance rates immediately after the storage, and capacity maintenance rates at the second cycle after the storage.
  • the capacities immediately before the storage were substantially equal for the battery A (3.92 mAh) and the battery B (3.90 mAh), while the battery C had a significantly lower capacity of 2.87 mAh.
  • the voltage immediately after the storage lowered to 0.1 V for the battery B, and the capacity maintenance rate at the second cycle after the storage dropped to 41%.
  • the battery A on the other hand, had 3.9 V for the voltage immediately after the storage, 53% for the capacity maintenance rate immediately after the storage, and 92% for the capacity maintenance rate at the second cycle after the storage. This clearly shows improvement in the high-temperature storage properties.
  • the battery C using the binder with high chemical stability showed no abrupt drop in the capacity maintenance rate but held 79% at the second cycle after the storage. This level is, however, relatively lower than that of the battery A, while the absolute capacity of the battery C is significantly smaller than that of the battery A.
  • a positive electrode was prepared by utilizing LiNiO 2 as an active material and various fluorocarbon elastomers as a binder.
  • Various elastomers of vinylidene fluoride-containing copolymers were used as a binder.
  • LiNiO 2 powder and acetylene black as a conductive agent were mixed in a weight ratio of 100:3, and added with a solution prepared by dissolving each copolymer in methyl isobutyl ketone to give a mixture of LiNiO 2 powder, the conductive agent, and the binder (solid content) at a weight ratio of 100:3:4.
  • the mixture was sufficiently kneaded and was added with a cross-linking agent to yield a paste.
  • the paste-like mixture was applied onto a current collector of aluminum foil, which was heated at 150° C. and dried sufficiently.
  • the current collector with the paste-like mixture applied thereon was pressed at a pressure of 2 ton/cm 2 , and was cut into a 10 mm square piece as a positive electrode plate.
  • the weight of the electrode mixture on the positive electrode plate was 20 mg.
  • Tetrahydrofuran was used as a solvent for the binder of an elastomer of tetrafluoroethylene-propylene copolymer, whereas methyl isobutyl ketone was used for the binder of an elastomer of trifluoropropylmethylsiloxane polymer.
  • Positive electrodes were manufactured in a similar manner to the above, using various binders and solvents.
  • Batteries were assembled with the positive electrodes thus obtained in the same manner as in Example 1.
  • Battery D2 has vinylidene fluoride-hexafluoropropylene copolymer as a binder of the positive electrode
  • battery E2 has vinylidene fluoride-pentafluoropropylene copolymer
  • battery F2 has vinylidene fluoride-chlorotrifluoroethylene copolymer
  • battery G2 has vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer
  • battery H2 has vinylidene fluoride-pentafluoropropylenetetrafluoroethylene copolymer
  • battery I2 has vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer
  • battery J2 has tetrafluoroethylene-propylene copolymer
  • battery K2 has trifluoropropylmethylsiloxane polymer
  • the charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V.
  • the condition of high-temperature storage was at 60° C. for 20 days under the charged condition of the second cycle.
  • Table 2 shows mean values of capacities immediately before the storage, voltages and capacity maintenance rates immediately after the storage, and capacity maintenance rates at the second cycle after the storage.
  • the batteries of Example 2 and the reference battery B had substantially equivalent capacities immediately before the storage.
  • the battery B had a lowered voltage of 0.1 V immediately after the storage and the capacity maintenance rate of 0% immediately after the storage and 41% even at the second cycle after the storage.
  • the batteries prepared in accordance with the present invention had the voltage of not less than 3.8 V immediately after the storage, not less than 50% for the capacity maintenance rate immediately after the storage, and not less than 90% for the capacity maintenance rate at the second cycle after the storage. This clearly shows improvement in the high-temperature storage properties.
  • the batteries D2, G2 and J2 of the present invention had the most excellent properties under more severe condition than the above, followed by the batteries E2 and He of the present invention.
  • fluorocarbon elastomers vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer and tetrafluoroethylenepropylene copolymer are most preferable for a binder.
  • Table 4 shows that the batteries of the present invention having fluorocarbon elastomers as a binder suffer from less capacity deterioration than the reference batteries and have improved cycle performance.
  • a positive electrode was prepared by utilizing LiMn 2 O 4 as an active material and various fluorocarbon elastomers as a binder.
  • Elastomers of various vinylidene fluoride-containing copolymers were used as a binder.
  • LiMn 2 O 4 powder and acetylene black as a conductive agent were mixed in a weight ratio of 100:8, and added with a solution prepared by dissolving each copolymer in methyl isobutyl ketone to give a mixture of LiMn 2 O 4 powder, the conductive agent, and the binder (solid content) at a weight ratio of 100:8:4.
  • the mixture was sufficiently kneaded and was added with a cross-linking agent to prepare a paste.
  • the paste-like mixture was applied onto a current collector of aluminum foil, which was heated at 150° C. and dried sufficiently.
  • the current collector with the paste-like mixture applied thereon was pressed at a pressure of 2 ton/cm 2 , and was cut into a 10 mm square piece as a positive electrode plate.
  • the weight of the electrode mixture on the positive electrode plate was 20 mg.
  • Tetrahydrofuran was used as a solvent for the binder of an elastomer of tetrafluoroethylene-propylene copolymer and an elastomer of trifluoropropylmethylsiloxane polymer.
  • Positive electrodes were manufactured in a similar manner to the above, using various binders and solvents.
  • Batteries were assembled with the positive electrodes thus obtained in the same manner as in Example 1.
  • Battery D3 has vinylidene fluoride-hexafluoropropylene copolymer as a binder of the positive electrode
  • battery E3 has vinylidene fluoride-pentafluoropropylene copolymer
  • battery F3 has vinylidene fluoride-chlorotrifluoroethylene copolymer
  • battery G3 has vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer
  • battery H3 has vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer
  • battery I3 has vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer
  • battery J3 has tetrafluoroethylene-propylene copolymer
  • battery K3 has trifluoropropylmethylsiloxane poly
  • a reference battery L was also prepared using a positive electrode having an aqueous dispersion of polytetrafluoroethylene as a binder.
  • the charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V.
  • Table 5 shows mean values of initial capacities and capacity maintenance rates at the 50th cycle for the respective batteries.
  • Table 5 shows that the batteries of the present invention having fluorocarbon elastomers as a binder suffer from less capacity deterioration than the polytetrafluoroethylene-containing reference battery and have improved cycle performance.
  • a positive electrode was prepared by utilizing LiCoO 2 as an active material, and tetrafluoroethylene-hexafluoropropylene copolymer dispersed in an organic solvent and vinylidene fluoride-hexafluoropropylene copolymer (a fluorocarbon elastomer) dissolved in an organic solvent, as binders, respectively.
  • a positive electrode having tetrafluoroethylene-hexafluoropropylene copolymer was prepared in a similar manner to that in Example 1 while preparation of a positive electrode having vinylidene fluoride-hexafluoropropylene copolymer followed the process of Example 2.
  • LiCoO 2 powders synthesized by combinations of three starting materials shown in Table 6 were used as a positive electrode active material. The heating temperature was 900° C. in all the cases.
  • a positive electrode having an aqueous dispersion of polytetrafluoroethylene as a binder was prepared as a reference.
  • Table 7 shows the incidence of application (i.e., coating) failure for fifty positive electrodes each.
  • the incidence of application failure was not greater than 2% for any of the positive electrode active materials 1, 2, and 3.
  • the incidence of application failure of the reference electrode was 2% for the active material 1 but undesirably high as 48% and 98% for the active materials 2 and 3, respectively.
  • Table 8 shows initial capacities and capacity maintenance rates at the 50th cycle for batteries prepared in the same manner as in Example 1 having the binders and positive electrode active materials specified above.
  • the charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.1 V.
  • any binders gave equivalent properties for those having the low incidence of application failure and poorer properties for those having the high incidence of application failure.
  • the vinylidene fluoride-hexafluoropropylene copolymer used as a binder had the highest capacity maintenance rate at the 50th cycle and improved cycle performance.
  • the fluorocarbon elastomers used in Examples 2, 3, and 4 may be cross-linked with a cross-linking agent such as polyamines, polyols, and peroxides.
  • any materials which allow reversible storage and discharge of lithium such as lithium-alloyed metals represented by metal aluminum and aluminum alloy, graphite-like compounds, metal lithium or lithium alloy, may be applied instead.
  • LiNiO 2 , LiCoO 2 , LiMnO 2 , and LiMn 2 O 4 were used for a positive electrode active material; the transition elements of these compounds, however, may be substituted by B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, or Rh.
  • the compounds containing transition metals partly substituted with these elements have effects of the present invention described above, though less effects in many cases.
  • the present invention is applicable to positive electrodes containing, as an active material, compounds represented by the general formula Li x (Mn 1-y M y ) 2 O 4 , wherein M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05 ⁇ x ⁇ 1.10, and 0 ⁇ y ⁇ 0.5.
  • lithium hexafluorophosphate was used as a lithium salt and ethylene carbonate and diethyl carbonate were used as the solvents of the electrolyte.
  • lithium salt other than lithium hexafluorophosphate include lithium perchlorate, lithium tetrafluoroborate, and lithium trifluoromethane sulfonate.
  • non-protonic solvents applicable to lithium secondary batteries other than ethylene carbonate and diethyl carbonate include propylene carbonate, dimethoxyethane, ⁇ -butyrolactone, dioxolane, tetrahydrofuran, methyltetrahydrofuran, and dimethyl sulfoxide.
  • tetrahydrofuran or methyltetrahydrofuran as the non-aqueous electrolyte for the binder of tetrafluoroethylene-hexafluoropropylene copolymer.
  • Organic solvents used for preparation of the paste-like active material were a mixture of xylene and cyclohexane in Example 1 and methyl isobutyl ketone and tetrahydrofuran in Example 2.
  • Other organic solvents including toluene, methyl acetate, butyl acetate, methyl ethyl ketone, methyltetrahydrofuran, and dimethylformamide may be applied independently or as a mixture for preparation of an active material paste.
  • the positive electrode active material, the conductive agent, and the binder were mixed in the weight ratio of 100:3:4.
  • the preferable contents of the positive electrode active material and the binder are not less than 70% and in a range of from 0.5 to 10% by weight, respectively.
  • the smaller content of positive electrode active material undesirably lowers the capacity of the positive electrode per unit weight or volume.
  • the greater amount of the binder prevents smooth current collection to lower the capacity, while the smaller amount reduces the strength of the electrode to deteriorate the properties.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

A positive electrode for a non-aqueous electrolyte lithium secondary battery comprises an active material represented by the formula LixA1-yMyO2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05</=x</=1.1, and 0</=y</=0.5), a binder, a conductive agent and a current collector. The binder is selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a positive electrode for non-aqueous electrolyte lithium secondary batteries and a method of manufacturing the same.
2. Description of the Prior Art
Non-aqueous electrolyte secondary batteries having a lithium or lithium compound negative electrode have been studied extensively for their potentials for high voltage and high energy density.
Positive electrode-active materials of non-aqueous electrolyte secondary batteries proposed hitherto include oxides of transition metals and chalcogen compounds, such as Lix CoO2, Lix Mn2 O4, Lix FeO2, Lix NiO2, V2 O5, Cr2 O5, MnO2, TiS2, MoS2, and the like.
These active materials have layers or tunnel-like crystal structures allowing intercalation and deintercalation of lithium ions. Especially Lix CoO2 (hereinafter referred to as LiCoO2), Lix NiO2 (hereinafter referred to as LiNiO2), Lix MnO2 (hereinafter referred to as LiMnO2), and Lix Mn2 O4 (hereinafter referred to as LiMn2 O4) are noted as 4V-class positive electrode active materials for non-aqueous electrolyte lithium secondary batteries. LiCoO2 is a most promising positive electrode active material because of its favorable properties.
While cobalt contained in LiCoO2 is relatively expensive, LiNiO2, which is cheaper and thus allows stable supply, has been noted recently. LiNiO2 has a similar composition and structure to those of LiCoO2 and is expected to give a high capacity and a high voltage as a positive electrode active material for lithium secondary batteries. Improved synthesis has increased the capacity of LiNiO2 to the level exceeding LiCoO2. LiMn2 O4 has also excellent properties with a slightly lower capacity, and LiMnO2 has also been studied extensively for practical applications.
Binders generally applied for preparation of positive electrodes with these active materials are required to be chemically inactive and stable against organic electrolyte. Polytetrafluoroethylene having a structural formula represented by the formula (1), which is a chemically inactive and stable resin, is widely used as the binder.
(--CF.sub.2 --CF.sub.2 --).sub.n                           ( 1)
A typical method applied to preparation of electrodes includes the steps of mixing an aqueous dispersion of a resin powder with an active material, a conductive agent and other additives to prepare a paste, and applying the paste onto current collectors or electrically-conductive electrode supports to form electrodes. Another method comprises mixing of a powdery binder with an active material, a conductive agent and other additives in dry stage and pressure-molds the mixture.
When these complex oxides containing lithium and a transition metal are used as a positive electrode active material for preparation of positive electrodes of lithium secondary batteries, properties of the electrodes thus obtained are significantly affected by various conditions including the type of a binder applied and the type of a dispersion medium in which a mixture of an active material, a binder, a conductive agent and other additives are dispersed.
Electrodes containing LiNiO2 as an active material have varying properties according to the types of a binder and a dispersion medium. This is partly ascribed to the high reactivity of LiNiO2 with water. LiNiO2 easily causes an ion exchange reaction between protons and lithium ions in the presence of water, thus lowering the capacity. The former method using water as a dispersion medium undesirably lowers the capacity.
Preparation of electrodes in dry state, on the other hand, causes insufficient dispersion of constituents, thereby lowering the capacity.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide a positive electrode for lithium secondary batteries having excellent properties.
The present invention provides a positive electrode for a non-aqueous electrolyte lithium secondary battery, which comprises a positive electrode active material represented by the general formula Lix A1-y My O2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, St, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5), a binder, a conductive agent and a current collector. The binder is at least one member selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.
The copolymer comprising a vinylidene fluoride unit is preferably selected from the group consisting of a copolymer comprising a vinylidene fluoride unit and a hexafluoropropylene unit; a copolymer comprising a vinylidene fluoride unit and a pentafluoropropylene unit; a copolymer comprising a vinylidene fluoride unit and a chlorotrifluoroethylene unit; a copolymer comprising a vinylidene fluoride unit, a hexafluoropropylene unit and a tetrafluoroethylene unit; a copolymer comprising a vinylidene fluoride unit, a pentafluoropropylene unit and a tetrafluoroethylene unit; and a copolymer comprising a vinylidene fluoride unit, a perfluoromethyl vinyl ether unit and a tetrafluoroethylene unit.
It is preferable that the copolymer comprising a vinylidene fluoride unit is an elastomer (fluorocarbon rubber) and cross-linked in a resultant electrode.
The present invention is also directed to a method of manufacturing a positive electrode for a non-aqueous electrolyte lithium secondary battery. The method comprises the steps of:
mixing a positive electrode active material represented by the general formula Lix A1-y My O2 (wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5), a binder, a conductive agent and an organic solvent to prepare a paste; and
applying the paste onto a current collector and drying the current collector. The binder is selected from the group consisting of a copolymer comprising a tetrafluoroethylene unit and a hexafluoropropylene unit, a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.
While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross sectional view illustrating a secondary battery in an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Completion of the present invention is based on examination of various binders and dispersion media or solvents applied to preparation of an electrode with a positive electrode active material, especially LiNiO2. Since water contained in an aqueous dispersion of polytetrafluoroethylene deteriorates properties of the active material as described previously, a dispersion in an organic solvent has been examined.
Of the polytetrafluoroethylenes, however, highly polymerized ones having a sufficient binding ability and therefore serving as a binder are difficult to disperse in an organic solvent. An electrode was therefore prepared in a non-aqueous system using as a binder polyvinylidene fluoride, which is a fluorocarbon resin soluble in some organic solvents and has a structural formula represented by the formula (2). A paste-like mixture was prepared by mixing polyvinylidene fluoride dissolved in an organic solvent with an active material and a conductive agent and applied onto a current collector to prepare an electrode plate.
(--CH.sub.2 --CF.sub.2 --).sub.n                           (2)
This gave a positive electrode having a higher capacity than that of LiCoO2. A non-aqueous electrolyte lithium secondary battery was then prepared using the LiNiO2 -containing positive electrode thus obtained. The charge and discharge properties test showed that the secondary battery had an excellent initial capacity but relatively poor storage properties. From the analysis of the secondary battery based on the charge and discharge properties test and the evaluation of reactivity of the electrode constituents, such poor storage properties are partly ascribed to the binder, polyvinylidene fluoride, which is swollen by and is dissolved in an organic electrolyte while reacting with the electrolyte salt.
Fluorocarbon resins and elastomers (fluorocarbon rubbers) given below have been selected for a binder, which is less active to the organic electrolyte than vinylidene fluoride polymer and allows preparation of electrodes in a non-aqueous system. These binders enable preparation of high-performance positive electrodes of lithium secondary batteries.
Applicable fluorocarbon resins and elastomers include tetrafluoroethylene-hexafluoropropylene copolymers represented by the formula (3), vinylidene fluoride-hexafluoropropylene copolymers represented by the formula (4), vinylidene fluoride-pentafluoropropylene copolymers represented by the formula (5), vinylidene fluoride-chlorotrifluoroethylene copolymers represented by the formula (6), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers represented by the formula (7), vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymers represented by the formula (8), vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymers represented by the formula (9), tetrafluoroethylene-propylene copolymers represented by the formula (10), and trifluoropropylmethylsiloxane polymers represented by the formula (11). ##STR1##
The above-mentioned copolymers may have any arrangement of monomer units, but preferably have compositions given below. The tetrafluoroethylene-hexafluoropropylene copolymer contains from 30 to 60 mol % of the tetrafluoroethylene unit, while the vinylidene fluoride-hexafluoropropylene copolymer and vinylidene fluoride-pentafluoropropylene copolymer contain from 50 to 85 mol % of the vinylidene fluoride unit. The vinylidene fluoride-chlorotrifluoroethylene copolymer contains from 50 to 75 mol % of the vinylidene fluoride unit, while the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer and vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer contain from 20 to 50 mol % of the vinylidene fluoride unit and not greater than 30 mol % of the tetrafluoroethylene unit. The vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer contains from 10 to 50 mol % of the vinylidene fluoride unit and not greater than 35 mol % of the tetrafluoroethylene unit, while the tetrafluoroethylene-propylene copolymer contains from 30 to 60 mol % of the tetrafluoroethylene unit.
The tetrafluoroethylene-hexafluoropropylene copolymer is effectively dispersed in an organic solvent and allows preparation of electrodes in a non-aqueous system. The tetrafluoroethylene-hexafluoropropylene copolymer is chemically stable as polytetrafluoroethylene and has excellent properties sufficient for a binder applied to positive electrodes of lithium secondary batteries.
The fluorocarbon elastomers (fluorocarbon rubbers) are soluble in some organic solvents and allow preparation of electrodes in a non-aqueous system. Cross-linking reactions of the elastomers enhance the properties including solvent resistance and heat resistance and give electrodes having sufficient chemical stability. These elastomers also improve the cycle performance, which constitute a drawback of LiNiO2 used as the positive electrode active material. The fluorocarbon elastomers (fluorocarbon rubbers) applied as a binder have sufficient elasticity to effectively prevent destruction of active material particles and electrodes due to a variation in volume of an active material in the charge and discharge process, thereby improving the cycle performance.
The present invention is also preferably applicable to electrodes containing a compound, such as LiCoO2 and LiMn2 O4, as an active material. In preparation of electrodes containing such a compound as an active material, an aqueous dispersion of polytetrafluoroethylene is conventionally used for preparation of a paste-like mixture of active material. Remaining lithium salts in the active material in the course of synthesis thereof increase the pH level of the paste, which may corrode the current collector or cause other troubles in preparation of electrodes.
A possible countermeasure taken improves the conditions of synthesis of an active material to prevent contamination by nonreacted lithium salts, while another countermeasure washes an active material powder with water prior to preparation of electrodes to remove remaining lithium salts. These countermeasures, which are generally time- and labor-consuming, are, however, significantly affected by varied qualities of starting materials for synthesis of an active material and may not yield electrodes having excellent properties and stability.
The present invention is applicable to LiCoO2 and LiMn2 O4 used as a positive electrode active material to yield stable and high-performance electrodes without being affected by the varying conditions of synthesis of an active material. The present invention does not cause any troubles including corrosion of the current collector at the raised pH due to dissolution of remaining lithium salts. The fluorocarbon elastomers (fluorocarbon rubbers) further improve the cycle performance of these compounds, like LiNiO2 described above.
As described above, the following polymers are applicable as a binder to give a positive electrode of lithium secondary batteries with excellent properties: tetrafluoroethylene-hexafluoropropylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers, vinylidene fluoride-pentafluoropropylene copolymers, vinylidene fluoride-chlorotrifluoroethylene copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymers, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymers, tetrafluoroethylenepropylene copolymers, and trifluoropropylmethylsiloxane polymers.
The following Examples are presented as specific illustrations of the invention. It should be understood, however, that the invention is not limited to the specific details set forth in the Examples.
EXAMPLE 1
In this example, a positive electrode was prepared by utilizing LiNiO2 as an active material and a dispersion of tetrafluoroethylene-hexafluoropropylene copolymer in an organic solvent as a binder.
A dispersion was prepared by dispersing tetrafluoroethylene-hexafluoropropylene copolymer powder in a mixture of xylene and cyclohexane. LiNiO2 powder and acetylene black as a conductive agent were mixed in a weight ratio of 100:3, and the resultant mixture was added with the dispersion to give a mixture of LiNiO2 powder, the conductive agent, and the binder (solid content) in a weight ratio of 100:3:4. The mixture was sufficiently kneaded to prepare a paste. The paste-like mixture was applied onto a current collector of aluminum foil, which was sufficiently dried and heated at 350° C. for one hour. The current collector with the paste-like mixture applied thereon was pressed at a pressure of 2 ton/cm2, and was cut into a 10 mm square piece as a positive electrode plate. The weight of the electrode mixture on the positive electrode plate was 20 mg.
FIG. 1 is a longitudinal cross sectional view illustrating a secondary battery having the positive electrode plate thus prepared. A positive electrode 1 having a current collector 8 was arranged on the center of a casing 2. A porous polypropylene film used as a separator 3 was disposed on the positive electrode 1. A negative electrode 4 was a carbon electrode prepared by applying a paste-like mixture of carbon powder and styrene-butadiene rubber (SBR) latex in a weight ratio (solid content) of 100:2 onto a current collector 6 of copper foil. A non-aqueous electrolyte was prepared by dissolving 1 mol/l lithium hexafluorophosphate in a mixture of ethylene carbonate and diethyl carbonate (1:1 by volume).
The electrolyte was poured onto the separator 3 in the casing 2 and onto the negative electrode 4 incorporated in a sealing plate 7. The sealing plate 7 with a gasket 5 and the casing 2 were then assembled to give a sealed battery. Since the negative electrode had a capacity sufficiently greater than that of the positive electrode, a capacity of the battery was restricted by the capacity of the positive electrode. This battery is hereinafter referred to as battery A.
A non-aqueous paste-like mixture containing polyvinylidene fluoride as a binder and N,N-dimethylformamide as a solvent for dissolving the binder was also prepared as a reference. A positive electrode was manufactured in a similar manner to the above, and a battery assembled with the positive electrode is hereinafter referred to as battery B. Another reference positive electrode was manufactured in a similar manner to the above using an aqueous dispersion of polytetrafluoroethylene as a binder, and a battery assembled with the positive electrode is hereinafter referred to as battery C.
High-temperature storage properties were evaluated for the respective ten batteries A, B and C.
The charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V. The condition of high-temperature storage was at 60° C. for 20 days under the charged condition of the second cycle. Table 1 shows mean values of capacities immediately before the storage, voltages and capacity maintenance rates immediately after the storage, and capacity maintenance rates at the second cycle after the storage.
              TABLE 1                                                     
______________________________________                                    
                       Capacity   Capacity                                
Capacity     Voltage   maintenance                                        
                                  maintenance                             
immediately  immedi-   rate immedi-                                       
                                  rate at 2nd                             
before stor- ately after                                                  
                       ately after                                        
                                  cycle after                             
age (mAh)    storage (V)                                                  
                       storage (%)                                        
                                  storage (%)                             
______________________________________                                    
Battery                                                                   
      3.92       3.9       53       92                                    
Battery                                                                   
      3.90       0.1        0       41                                    
B                                                                         
Battery                                                                   
      2.87       3.4       27       79                                    
C                                                                         
______________________________________
As clearly shown in Table 1, the capacities immediately before the storage were substantially equal for the battery A (3.92 mAh) and the battery B (3.90 mAh), while the battery C had a significantly lower capacity of 2.87 mAh. The voltage immediately after the storage lowered to 0.1 V for the battery B, and the capacity maintenance rate at the second cycle after the storage dropped to 41%. The battery A, on the other hand, had 3.9 V for the voltage immediately after the storage, 53% for the capacity maintenance rate immediately after the storage, and 92% for the capacity maintenance rate at the second cycle after the storage. This clearly shows improvement in the high-temperature storage properties. The battery C using the binder with high chemical stability showed no abrupt drop in the capacity maintenance rate but held 79% at the second cycle after the storage. This level is, however, relatively lower than that of the battery A, while the absolute capacity of the battery C is significantly smaller than that of the battery A.
EXAMPLE 2
In this example, a positive electrode was prepared by utilizing LiNiO2 as an active material and various fluorocarbon elastomers as a binder.
Various elastomers of vinylidene fluoride-containing copolymers were used as a binder. LiNiO2 powder and acetylene black as a conductive agent were mixed in a weight ratio of 100:3, and added with a solution prepared by dissolving each copolymer in methyl isobutyl ketone to give a mixture of LiNiO2 powder, the conductive agent, and the binder (solid content) at a weight ratio of 100:3:4. The mixture was sufficiently kneaded and was added with a cross-linking agent to yield a paste. The paste-like mixture was applied onto a current collector of aluminum foil, which was heated at 150° C. and dried sufficiently. The current collector with the paste-like mixture applied thereon was pressed at a pressure of 2 ton/cm2, and was cut into a 10 mm square piece as a positive electrode plate. The weight of the electrode mixture on the positive electrode plate was 20 mg.
Tetrahydrofuran was used as a solvent for the binder of an elastomer of tetrafluoroethylene-propylene copolymer, whereas methyl isobutyl ketone was used for the binder of an elastomer of trifluoropropylmethylsiloxane polymer. Positive electrodes were manufactured in a similar manner to the above, using various binders and solvents.
Batteries were assembled with the positive electrodes thus obtained in the same manner as in Example 1. Battery D2 has vinylidene fluoride-hexafluoropropylene copolymer as a binder of the positive electrode, battery E2 has vinylidene fluoride-pentafluoropropylene copolymer, battery F2 has vinylidene fluoride-chlorotrifluoroethylene copolymer, battery G2 has vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, battery H2 has vinylidene fluoride-pentafluoropropylenetetrafluoroethylene copolymer, battery I2 has vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, battery J2 has tetrafluoroethylene-propylene copolymer, and battery K2 has trifluoropropylmethylsiloxane polymer.
The batteries B and C prepared in Example 1 were used as references for Example 2.
High-temperature storage properties were evaluated for ten batteries each.
The charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V. The condition of high-temperature storage was at 60° C. for 20 days under the charged condition of the second cycle. Table 2 shows mean values of capacities immediately before the storage, voltages and capacity maintenance rates immediately after the storage, and capacity maintenance rates at the second cycle after the storage.
              TABLE 2                                                     
______________________________________                                    
                       Capacity   Capacity                                
Capacity     Voltage   maintenance                                        
                                  maintenance                             
immediately  immedi-   rate immedi-                                       
                                  rate at 2nd                             
before stor- ately after                                                  
                       ately after                                        
                                  cycle after                             
age (mAh)    storage (V)                                                  
                       storage (%)                                        
                                  storage (%)                             
______________________________________                                    
Battery                                                                   
      3.90       0.1        0       41                                    
Battery                                                                   
      3.91       3.9       53       91                                    
D2                                                                        
Battery                                                                   
      3.91       3.8       51       90                                    
E2                                                                        
Battery                                                                   
      3.90       3.9       53       91                                    
F2                                                                        
Battery                                                                   
      3.91       3.9       55       92                                    
G2                                                                        
Battery                                                                   
      3.91       3.9       55       92                                    
H2                                                                        
Battery                                                                   
      3.90       3.8       51       90                                    
I2                                                                        
Battery                                                                   
      3.91       3.9       55       92                                    
J2                                                                        
Battery                                                                   
      3.90       3.8       50       90                                    
K2                                                                        
______________________________________
As clearly shown in Table 2, the batteries of Example 2 and the reference battery B had substantially equivalent capacities immediately before the storage. The battery B had a lowered voltage of 0.1 V immediately after the storage and the capacity maintenance rate of 0% immediately after the storage and 41% even at the second cycle after the storage. The batteries prepared in accordance with the present invention, on the other hand, had the voltage of not less than 3.8 V immediately after the storage, not less than 50% for the capacity maintenance rate immediately after the storage, and not less than 90% for the capacity maintenance rate at the second cycle after the storage. This clearly shows improvement in the high-temperature storage properties.
Then, properties of the batteries of the present invention and the reference battery B were evaluated after storage for three days at 85° C. under the charged condition of the second cycle in a similar manner to the above. Table 3 shows the results of this evaluation.
              TABLE 3                                                     
______________________________________                                    
                       Capacity   Capacity                                
Capacity     Voltage   maintenance                                        
                                  maintenance                             
immediately  immedi-   rate immedi-                                       
                                  rate at 2nd                             
before stor- ately after                                                  
                       ately after                                        
                                  cycle after                             
age (mAh)    storage (V)                                                  
                       storage (%)                                        
                                  storage (%)                             
______________________________________                                    
Battery                                                                   
      3.90        0.07      0       22                                    
Battery                                                                   
      3.91       3.8       51       89                                    
D2                                                                        
Battery                                                                   
      3.91       3.7       49       82                                    
E2                                                                        
Battery                                                                   
      3.90       3.6       38       73                                    
F2                                                                        
Battery                                                                   
      3.91       3.8       51       89                                    
G2                                                                        
Battery                                                                   
      3.91       3.7       49       83                                    
H2                                                                        
Battery                                                                   
      3.90       3.7       33       69                                    
I2                                                                        
Battery                                                                   
      3.91       3.8       51       89                                    
J2                                                                        
Battery                                                                   
      3.90       3.6       31       65                                    
K2                                                                        
______________________________________
As clearly seen in Table 3, the batteries D2, G2 and J2 of the present invention had the most excellent properties under more severe condition than the above, followed by the batteries E2 and He of the present invention.
Thus, it is understood that of the fluorocarbon elastomers, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer and tetrafluoroethylenepropylene copolymer are most preferable for a binder.
Cycle properties were also evaluated for newly prepared ten batteries each. Table 4 shows mean values of initial capacities and capacity maintenance rates at the 50th cycle for the respective batteries.
              TABLE 4                                                     
______________________________________                                    
                   Capacity maintenance rate at                           
Initial capacity (mAh)                                                    
                   50th cycle (%)                                         
______________________________________                                    
Battery A                                                                 
        3.92           82                                                 
Battery B                                                                 
        3.90           76                                                 
Battery C                                                                 
        2.87           81                                                 
Battery D2                                                                
        3.91           90                                                 
Battery E2                                                                
        3.91           90                                                 
Battery F2                                                                
        3.90           90                                                 
Battery G2                                                                
        3.91           91                                                 
Battery H2                                                                
        3.91           91                                                 
Battery I2                                                                
        3.90           90                                                 
Battery J2                                                                
        3.91           91                                                 
Battery K2                                                                
        3.90           90                                                 
______________________________________
Table 4 shows that the batteries of the present invention having fluorocarbon elastomers as a binder suffer from less capacity deterioration than the reference batteries and have improved cycle performance.
EXAMPLE 3
In this example, a positive electrode was prepared by utilizing LiMn2 O4 as an active material and various fluorocarbon elastomers as a binder.
Elastomers of various vinylidene fluoride-containing copolymers were used as a binder. LiMn2 O4 powder and acetylene black as a conductive agent were mixed in a weight ratio of 100:8, and added with a solution prepared by dissolving each copolymer in methyl isobutyl ketone to give a mixture of LiMn2 O4 powder, the conductive agent, and the binder (solid content) at a weight ratio of 100:8:4. The mixture was sufficiently kneaded and was added with a cross-linking agent to prepare a paste. The paste-like mixture was applied onto a current collector of aluminum foil, which was heated at 150° C. and dried sufficiently. The current collector with the paste-like mixture applied thereon was pressed at a pressure of 2 ton/cm2, and was cut into a 10 mm square piece as a positive electrode plate. The weight of the electrode mixture on the positive electrode plate was 20 mg.
Tetrahydrofuran was used as a solvent for the binder of an elastomer of tetrafluoroethylene-propylene copolymer and an elastomer of trifluoropropylmethylsiloxane polymer. Positive electrodes were manufactured in a similar manner to the above, using various binders and solvents.
Batteries were assembled with the positive electrodes thus obtained in the same manner as in Example 1. Battery D3 has vinylidene fluoride-hexafluoropropylene copolymer as a binder of the positive electrode, battery E3 has vinylidene fluoride-pentafluoropropylene copolymer, battery F3 has vinylidene fluoride-chlorotrifluoroethylene copolymer, battery G3 has vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, battery H3 has vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer, battery I3 has vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, battery J3 has tetrafluoroethylene-propylene copolymer, and battery K3 has trifluoropropylmethylsiloxane polymer.
A reference battery L was also prepared using a positive electrode having an aqueous dispersion of polytetrafluoroethylene as a binder.
Cycle properties were also evaluated for ten batteries each.
The charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.2 V. Table 5 shows mean values of initial capacities and capacity maintenance rates at the 50th cycle for the respective batteries.
              TABLE 5                                                     
______________________________________                                    
                   Capacity maintenance rate at                           
Initial capacity (mAh)                                                    
                   50th cycle (%)                                         
______________________________________                                    
Battery D3                                                                
        2.21           87                                                 
Battery E3                                                                
        2.21           86                                                 
Battery F3                                                                
        2.20           86                                                 
Battery G3                                                                
        2.21           87                                                 
Battery H3                                                                
        2.20           87                                                 
Battery I3                                                                
        2.20           86                                                 
Battery J3                                                                
        2.21           87                                                 
Battery K3                                                                
        2.20           86                                                 
Battery L                                                                 
        2.20           71                                                 
______________________________________
Table 5 shows that the batteries of the present invention having fluorocarbon elastomers as a binder suffer from less capacity deterioration than the polytetrafluoroethylene-containing reference battery and have improved cycle performance.
EXAMPLE 4
In this example, a positive electrode was prepared by utilizing LiCoO2 as an active material, and tetrafluoroethylene-hexafluoropropylene copolymer dispersed in an organic solvent and vinylidene fluoride-hexafluoropropylene copolymer (a fluorocarbon elastomer) dissolved in an organic solvent, as binders, respectively.
A positive electrode having tetrafluoroethylene-hexafluoropropylene copolymer was prepared in a similar manner to that in Example 1 while preparation of a positive electrode having vinylidene fluoride-hexafluoropropylene copolymer followed the process of Example 2. In Example 4, LiCoO2 powders synthesized by combinations of three starting materials shown in Table 6 were used as a positive electrode active material. The heating temperature was 900° C. in all the cases.
              TABLE 6                                                     
______________________________________                                    
                 Mixing ratio                                             
Co material      of Co/Li   Li material                                   
______________________________________                                    
Active  Guaranteed grade                                                  
                     1.04       Guaranteed grade                          
material 1                                                                
        Co.sub.3 O.sub.4        Li.sub.2 CO.sub.3                         
Active  First grade  1.04       Guaranteed grade                          
material 2                                                                
        Co.sub.3 O.sub.4        Li.sub.2 CO.sub.3                         
Active  Guaranteed grade                                                  
                     1.00       Guaranteed grade                          
material 3                                                                
        Co.sub.3 O.sub.4        Li.sub.2 CO.sub.3                         
______________________________________
A positive electrode having an aqueous dispersion of polytetrafluoroethylene as a binder was prepared as a reference.
Table 7 shows the incidence of application (i.e., coating) failure for fifty positive electrodes each.
              TABLE 7                                                     
______________________________________                                    
             Incidence of application (coating)                           
             failure (%)                                                  
             Active  Active    Active                                     
             material 1                                                   
                     material 2                                           
                               material 3                                 
______________________________________                                    
Tetrafluoroethylenehexa-                                                  
               0         1         2                                      
fluoropropylene copoly-                                                   
mer                                                                       
Vinylidene fluoridehexa-                                                  
               0         2         2                                      
fluoropropylene copoly-                                                   
mer                                                                       
Polytetrafluoroethylene                                                   
               1         48        98                                     
(aqueous dispersion)                                                      
______________________________________
When tetrafluoroethylene-hexafluoropropylene copolymer or vinylidene fluoride-hexafluoropropylene copolymer was used as a binder, the incidence of application failure was not greater than 2% for any of the positive electrode active materials 1, 2, and 3. The incidence of application failure of the reference electrode was 2% for the active material 1 but undesirably high as 48% and 98% for the active materials 2 and 3, respectively.
Table 8 shows initial capacities and capacity maintenance rates at the 50th cycle for batteries prepared in the same manner as in Example 1 having the binders and positive electrode active materials specified above.
The charge and discharge was carried out at a constant current of 0.5 mA in a voltage range of 3.0-4.1 V.
              TABLE 8                                                     
______________________________________                                    
             Initial capacity (mAh)/Capacity                              
             maintenance rate at 50th cycle (%)                           
             Active  Active    Active                                     
             material 1                                                   
                     material 2                                           
                               material 3                                 
______________________________________                                    
Tetrafluoroethylenehexa-                                                  
               2.36      2.35      2.34                                   
fluoropropylene copoly-                                                   
               98        98        98                                     
mer                                                                       
Vinylidene fluoridehexa-                                                  
               2.36      2.34      2.34                                   
fluoropropylene copoly-                                                   
               99        99        99                                     
mer                                                                       
Polytetrafluoroethylene                                                   
               2.34      2.21      1.99                                   
(aqueous dispersion)                                                      
               96        87        51                                     
______________________________________
As shown in Table 8, any binders gave equivalent properties for those having the low incidence of application failure and poorer properties for those having the high incidence of application failure. The vinylidene fluoride-hexafluoropropylene copolymer used as a binder had the highest capacity maintenance rate at the 50th cycle and improved cycle performance.
When LiCoO2 was used as a positive electrode active material, preparation in a non-aqueous system gave stable positive electrodes having excellent properties without effects of remaining lithium salts. This process also effectively lowers the ratio of application failure irrespective of the purity of LiCoO2 applied. This reduces the time and labor required for troublesome quality maintenance of materials significantly affecting the purity of LiCoO2.
Substantial elimination of effects of the remaining lithium salts is also observed in other lithium-containing oxides such as LiNiO2, LiMnO2, and LiMn2 O4 used as a positive electrode active material, as well as LiCoO2.
Although vinylidene fluoride-hexafluoropropylene copolymer was used as the fluorocarbon elastomer in the above-mentioned Example, pastes in an organic solvent of vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, tetrafluoroethylene-propylene copolymer, and trifluoropropylmethylsiloxane polymer have the equivalent effects.
The fluorocarbon elastomers used in Examples 2, 3, and 4 may be cross-linked with a cross-linking agent such as polyamines, polyols, and peroxides.
Although carbon was used for a negative electrode active material in the above-mentioned Examples, any materials which allow reversible storage and discharge of lithium, such as lithium-alloyed metals represented by metal aluminum and aluminum alloy, graphite-like compounds, metal lithium or lithium alloy, may be applied instead.
In the above-mentioned embodiments, LiNiO2, LiCoO2, LiMnO2, and LiMn2 O4 were used for a positive electrode active material; the transition elements of these compounds, however, may be substituted by B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, or Rh. The compounds containing transition metals partly substituted with these elements have effects of the present invention described above, though less effects in many cases.
The present invention is applicable to positive electrodes containing, as an active material, compounds represented by the general formula Lix (Mn1-y My)2 O4, wherein M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.10, and 0≦y≦0.5.
In the above-mentioned Embodiments, lithium hexafluorophosphate was used as a lithium salt and ethylene carbonate and diethyl carbonate were used as the solvents of the electrolyte. Examples of possible lithium salt other than lithium hexafluorophosphate include lithium perchlorate, lithium tetrafluoroborate, and lithium trifluoromethane sulfonate. Examples of non-protonic solvents applicable to lithium secondary batteries other than ethylene carbonate and diethyl carbonate include propylene carbonate, dimethoxyethane, γ-butyrolactone, dioxolane, tetrahydrofuran, methyltetrahydrofuran, and dimethyl sulfoxide.
It is not preferable, however, to use tetrahydrofuran or methyltetrahydrofuran as the non-aqueous electrolyte for the binder of tetrafluoroethylene-hexafluoropropylene copolymer.
Organic solvents used for preparation of the paste-like active material were a mixture of xylene and cyclohexane in Example 1 and methyl isobutyl ketone and tetrahydrofuran in Example 2. Other organic solvents including toluene, methyl acetate, butyl acetate, methyl ethyl ketone, methyltetrahydrofuran, and dimethylformamide may be applied independently or as a mixture for preparation of an active material paste.
In the above-mentioned Examples, the positive electrode active material, the conductive agent, and the binder were mixed in the weight ratio of 100:3:4. The preferable contents of the positive electrode active material and the binder are not less than 70% and in a range of from 0.5 to 10% by weight, respectively. The smaller content of positive electrode active material undesirably lowers the capacity of the positive electrode per unit weight or volume. The greater amount of the binder prevents smooth current collection to lower the capacity, while the smaller amount reduces the strength of the electrode to deteriorate the properties.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains, after having read the above-mentioned disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Claims (13)

What is claimed is:
1. A positive electrode for a non-aqueous electrolyte lithium secondary battery, which comprises a positive electrode active material represented by the general formula Lix A1-y My O2 wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5; a binder; a conductive agent; and a current collector,
wherein said binder is at least one member selected from the group consisting of a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit.
2. A positive electrode in accordance with claim 1, wherein said copolymer comprising a vinylidene fluoride unit is an elastomer selected from the group consisting of:
a copolymer comprising a vinylidene fluoride unit and a hexafluoropropylene unit,
a copolymer comprising a vinylidene fluoride unit and a pentafluoropropylene unit,
a copolymer comprising a vinylidene fluoride unit and a chlorotrifluoroethylene unit,
a copolymer comprising a vinylidene fluoride unit, a hexafluoropropylene unit and a tetrafluoroethylene unit,
a copolymer comprising a vinylidene fluoride unit, a pentafluoropropylene unit and a tetrafluoroethylene unit, and
a copolymer comprising a vinylidene fluoride unit, a perfluoromethyl vinyl ether unit and a tetrafluoroethylene unit.
3. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit and the hexafluoropropylene unit is vinylidene fluoride-hexafluoropropylene copolymer having 50-85 mol % of the vinylidene fluoride unit.
4. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit and the pentafluoropropylene unit is vinylidene fluoride-pentafluoropropylene copolymer having 50-85 mol % of the vinylidene fluoride unit.
5. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit and the chlorotrifluoroethylene unit is vinylidene fluoride-chlorotrifluoroethylene copolymer having 50-75 mol % of the vinylidene fluoride unit.
6. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit, hexafluoropropylene unit, and tetrafluoroethylene unit is vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer having 20-50 mol % of the vinylidene fluoride unit and not greater than 30 mol % of the tetrafluoroethylene unit.
7. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit, pentafluoropropylene unit, and tetrafluoroethylene unit is vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer having 20-50 mol % of the vinylidene fluoride unit and not greater than 30 mol % of the tetrafluoroethylene unit.
8. A positive electrode in accordance with claim 2, wherein said copolymer comprising the vinylidene fluoride unit, perfluoromethyl vinyl ether unit, and tetrafluoroethylene unit is vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer having 10-50 mol % of the vinylidene fluoride unit and not greater than 35 mol % of the tetrafluoroethylene unit.
9. A positive electrode in accordance with claim 1, wherein said copolymer comprising the propylene unit and tetrafluoroethylene unit is propylene-tetrafluroethylene copolymer having 30-60 mol % of the tetrafluorethlene unit.
10. A method of manufacturing a positive electrode for a non-aqueous electrolyte lithium secondary battery, which comprises the steps of:
mixing a positive electrode active material represented by the general formula Lix A1-y My O2 wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5; a binder; a conductive agent; and an organic solvent to prepare a paste-like electrode mixture,
wherein said binder is selected from the group consisting of a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit; and
applying said paste-like electrode mixture onto a current collector and drying.
11. A method of manufacturing a positive electrode for a non-aqueous electrolyte lithium secondary battery, which comprises the steps of:
mixing a positive electrode active material represented by the general formula Lix A1-y My O2 wherein A represents at least one transition element selected from the group consisting of Mn, Co, and Ni, M represents at least one element selected from the group consisting of B, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, In, Nb, Mo, W, Y, and Rh, and wherein 0.05≦x≦1.1, and 0≦y≦0.5; a binder; a conductive agent; and an organic solvent for dissolving said binder to prepare a paste-like electrode mixture,
wherein said binder is selected from the group consisting of a copolymer comprising a vinylidene fluoride unit, a copolymer comprising a propylene unit and a tetrafluoroethylene unit, and a polymer comprising a trifluoropropylmethylsiloxane unit; and
applying said paste-like electrode mixture onto a current collector and drying.
12. A positive electrode for a non-aqueous electrolyte lithium secondary battery wherein the electrode is manufactured according to the method of claim 10.
13. A positive electrode for a non-aqueous electrolyte lithium secondary battery wherein the electrode is manufactured according to the method of claim 11.
US08/439,218 1994-05-13 1995-05-11 Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same Expired - Lifetime US5609975A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP6-099989 1994-05-13
JP9998994 1994-05-13

Publications (1)

Publication Number Publication Date
US5609975A true US5609975A (en) 1997-03-11

Family

ID=14262063

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/439,218 Expired - Lifetime US5609975A (en) 1994-05-13 1995-05-11 Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same

Country Status (1)

Country Link
US (1) US5609975A (en)

Cited By (53)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5718989A (en) * 1995-12-29 1998-02-17 Japan Storage Battery Co., Ltd. Positive electrode active material for lithium secondary battery
US5766796A (en) * 1997-05-06 1998-06-16 Eic Laboratories, Inc. Passivation-free solid state battery
US5900385A (en) * 1997-10-15 1999-05-04 Minnesota Mining And Manufacturing Company Nickel--containing compounds useful as electrodes and method for preparing same
US6017654A (en) * 1997-08-04 2000-01-25 Carnegie Mellon University Cathode materials for lithium-ion secondary cells
US6045950A (en) * 1998-06-26 2000-04-04 Duracell Inc. Solvent for electrolytic solutions
US6051343A (en) * 1996-09-25 2000-04-18 Tdk Corporation Polymeric solid electrolyte and lithium secondary cell using the same
US6078007A (en) * 1998-01-15 2000-06-20 Lidow; Nicholai Hart Selenium photo generator cell with fluid top electrode
US6114061A (en) * 1998-02-12 2000-09-05 Micron Technology, Inc. Battery electrodes, batteries, and methods of forming batteries and battery electrodes
US6136470A (en) * 1998-02-20 2000-10-24 Micron Technology, Inc. Battery electrodes, batteries, and methods of forming batteries and battery electrodes
WO2000063923A1 (en) * 1999-04-16 2000-10-26 Massachusetts Institute Of Technology Layered lithium manganese compounds
US6248477B1 (en) 1999-09-29 2001-06-19 Kerr-Mcgee Chemical Llc Cathode intercalation compositions, production methods and rechargeable lithium batteries containing the same
US6265107B1 (en) * 1996-12-16 2001-07-24 Daikin Industries, Ltd. Binder for rechargeable battery with nonaqueous electrolyte and battery electrode depolarizing mix prepared using the same
US6267943B1 (en) 1998-10-15 2001-07-31 Fmc Corporation Lithium manganese oxide spinel compound and method of preparing same
US6277521B1 (en) 1997-05-15 2001-08-21 Fmc Corporation Lithium metal oxide containing multiple dopants and method of preparing same
US6350543B2 (en) * 1999-12-29 2002-02-26 Kimberly-Clark Worldwide, Inc. Manganese-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US6361756B1 (en) 1998-11-20 2002-03-26 Fmc Corporation Doped lithium manganese oxide compounds and methods of preparing same
US6399246B1 (en) 2000-05-05 2002-06-04 Eveready Battery Company, Inc. Latex binder for non-aqueous battery electrodes
US6416902B1 (en) * 1997-04-24 2002-07-09 Fuji Photo Film Co., Ltd. Non-aqueous lithium ion secondary battery
US6436574B1 (en) * 1999-04-26 2002-08-20 Nec Corporation Nonaqueous electrolyte secondary battery
US6482550B1 (en) * 1999-11-12 2002-11-19 Sanyo Electric Co., Ltd. Non-aqueous secondary battery
US20020177041A1 (en) * 2001-05-25 2002-11-28 Microbatterie Gmbh Method for producing electrode sheets for electrochemical elements
US20020197533A1 (en) * 1997-05-15 2002-12-26 Yuan Gao Metal oxide containing multiple dopants and method of preparing same
US20030017394A1 (en) * 2001-07-04 2003-01-23 Matsushita Electric Industrial Co., Ltd. And Asahi Glass Company, Limited Positive electrode for alkaline storage battery
US20030027048A1 (en) * 2001-04-27 2003-02-06 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US6579475B2 (en) 1999-12-10 2003-06-17 Fmc Corporation Lithium cobalt oxides and methods of making same
US6582854B1 (en) * 1999-12-02 2003-06-24 The Honjo Chemical Corporation Lithium ion secondary battery, cathode active material therefor and production thereof
US6589499B2 (en) 1998-11-13 2003-07-08 Fmc Corporation Layered lithium cobalt oxides free of localized cubic spinel-like structural phases and method of making same
WO2003092099A1 (en) * 2002-04-23 2003-11-06 Lg Chem. Ltd. Complex lithium metal oxides with enhanced cycle life and safety and a process for preparation thereof
US20040121234A1 (en) * 2002-12-23 2004-06-24 3M Innovative Properties Company Cathode composition for rechargeable lithium battery
US6761997B2 (en) * 2000-03-03 2004-07-13 Nissan Motor Co., Ltd. Positive electrode material and battery for nonaquous electrolyte secondary battery
US20040214086A1 (en) * 2001-07-14 2004-10-28 Bruce Peter George Electrochemical cells
US20050112054A1 (en) * 2003-11-26 2005-05-26 3M Innovative Properties Company Solid state synthesis of lithium ion battery cathode material
WO2004097961A3 (en) * 2003-04-30 2005-07-07 Univ Montreal Polymeric binder for fused salts electrolytes based batteries
US20050198815A1 (en) * 2001-09-14 2005-09-15 Matsushita Electric Industrial Co., Ltd. Non-aqueous electrolyte secondary battery and production method thereof
US6998069B1 (en) * 1999-12-03 2006-02-14 Ferro Gmbh Electrode material for positive electrodes of rechargeable lithium batteries
US7026071B2 (en) 1996-10-11 2006-04-11 Massachusetts Institute Of Technology Non-crosslinked, amorphous, block copolymer electrolyte for batteries
US20060159994A1 (en) * 2001-08-07 2006-07-20 Dahn Jeffrey R Cathode compositions for lithium ion batteries
US20070015055A1 (en) * 2003-04-09 2007-01-18 Lee Jae H Cathode active material comprising additive for improving overdischarge-performance and lithium secondary battery using the same
US20070031732A1 (en) * 2005-08-08 2007-02-08 A123 Systems, Inc. Nanoscale ion storage materials
US20070190418A1 (en) * 2005-08-08 2007-08-16 A123 Systems, Inc. Nanoscale ion storage materials
US20070292747A1 (en) * 2005-08-08 2007-12-20 Yet-Ming Chiang Amorphous and partially amorphous nanoscale ion storage materials
WO2007064934A3 (en) * 2005-12-02 2008-05-15 A123 Systems Inc Amorphous and partially amorphous nanoscale ion storage materials
US20100203386A1 (en) * 2002-03-22 2010-08-12 Lg Chem, Ltd. Cathode active material for lithium secondary battery
US20110045360A1 (en) * 2009-02-06 2011-02-24 Masaki Deguchi Lithium ion secondary battery and method for producing lithium ion secondary battery
US20110053003A1 (en) * 2009-02-06 2011-03-03 Masaki Deguchi Lithium ion secondary battery and method for producing lithium ion secondary battery
CN101826640B (en) * 2009-03-02 2013-01-02 上海比亚迪有限公司 Pole core for lithium ion battery and lithium ion battery using pole core
US8883348B2 (en) 2005-07-28 2014-11-11 Panasonic Corporation Electrode for lithium ion secondary battery
EP2624341A4 (en) * 2010-09-30 2015-10-07 Asahi Glass Co Ltd POSITIVE ELECTRODE MATERIAL MIXTURE FOR NONAQUEOUS SECONDARY CELL, AND POSITIVE ELECTRODE FOR NONAQUEOUS SECONDARY CELL AND SECONDARY CELL USING SAME
US9490484B2 (en) 2012-03-28 2016-11-08 Asahi Glass Company, Limited Binder for storage battery device
US10147944B2 (en) 2015-08-04 2018-12-04 Samsung Electronics Co., Ltd. Cathode including sintered polycrystalline material, secondary battery including the cathode, and method of manufacturing the cathode
WO2019219788A1 (en) * 2018-05-17 2019-11-21 Solvay Specialty Polymers Italy S.P.A. Electrode-forming compositions
US11571684B2 (en) * 2020-10-22 2023-02-07 Uchicago Argonne, Llc Lithium ion battery cathode and anode materials as tunable and dynamically responsive support materials for single site heterogeneous catalysis
CN116250100A (en) * 2020-09-30 2023-06-09 松下知识产权经营株式会社 Positive electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5569960A (en) * 1978-11-17 1980-05-27 Matsushita Electric Ind Co Ltd Manufacturing method for nonaqueous electrolyte cell
US4710335A (en) * 1984-06-13 1987-12-01 Central Glass Company, Limited Method of producing electric cell anode using powdery active material
JPH01304664A (en) * 1988-06-01 1989-12-08 Sony Corp Nonaqueous electrolyte secondary battery
US4940605A (en) * 1986-06-09 1990-07-10 Whittaker Technical Products, Inc. Electrode for electrochemical cell
US4964877A (en) * 1986-01-14 1990-10-23 Wilson Greatbatch Ltd. Non-aqueous lithium battery
JPH03108264A (en) * 1989-09-22 1991-05-08 Toshiba Battery Co Ltd Manufacture of positive electrode for nonaqueous solvent secondary battery
JPH056779A (en) * 1991-06-27 1993-01-14 Matsushita Electric Ind Co Ltd Non-aqueous electrolyte secondary battery
US5286582A (en) * 1990-11-02 1994-02-15 Seiko Electronic Components Ltd. Monaqueous electrolyte secondary battery and process for producing positive active materials
US5316875A (en) * 1991-07-19 1994-05-31 Matsushita Electric Industrial Co., Ltd. Secondary battery with nonaqueous electrolyte and method of manufacturing same
US5409786A (en) * 1993-02-05 1995-04-25 Eveready Battery Company, Inc. Inactive electrochemical cell having an ionically nonconductive polymeric composition activated by electrolyte salt solution
US5443601A (en) * 1993-05-03 1995-08-22 Regents, University Of California Method for intercalating alkali metal ions into carbon electrodes

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5569960A (en) * 1978-11-17 1980-05-27 Matsushita Electric Ind Co Ltd Manufacturing method for nonaqueous electrolyte cell
US4710335A (en) * 1984-06-13 1987-12-01 Central Glass Company, Limited Method of producing electric cell anode using powdery active material
US4964877A (en) * 1986-01-14 1990-10-23 Wilson Greatbatch Ltd. Non-aqueous lithium battery
US4940605A (en) * 1986-06-09 1990-07-10 Whittaker Technical Products, Inc. Electrode for electrochemical cell
JPH01304664A (en) * 1988-06-01 1989-12-08 Sony Corp Nonaqueous electrolyte secondary battery
JPH03108264A (en) * 1989-09-22 1991-05-08 Toshiba Battery Co Ltd Manufacture of positive electrode for nonaqueous solvent secondary battery
US5286582A (en) * 1990-11-02 1994-02-15 Seiko Electronic Components Ltd. Monaqueous electrolyte secondary battery and process for producing positive active materials
JPH056779A (en) * 1991-06-27 1993-01-14 Matsushita Electric Ind Co Ltd Non-aqueous electrolyte secondary battery
US5316875A (en) * 1991-07-19 1994-05-31 Matsushita Electric Industrial Co., Ltd. Secondary battery with nonaqueous electrolyte and method of manufacturing same
US5409786A (en) * 1993-02-05 1995-04-25 Eveready Battery Company, Inc. Inactive electrochemical cell having an ionically nonconductive polymeric composition activated by electrolyte salt solution
US5443601A (en) * 1993-05-03 1995-08-22 Regents, University Of California Method for intercalating alkali metal ions into carbon electrodes

Cited By (98)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5795558A (en) * 1995-12-29 1998-08-18 Japan Storage Battery Co., Ltd. Positive electrode active material for lithium secondary battery method of producing
US5718989A (en) * 1995-12-29 1998-02-17 Japan Storage Battery Co., Ltd. Positive electrode active material for lithium secondary battery
US6051343A (en) * 1996-09-25 2000-04-18 Tdk Corporation Polymeric solid electrolyte and lithium secondary cell using the same
US20080099734A1 (en) * 1996-10-11 2008-05-01 Massachusetts Institute Of Technology Intercalation compounds for batteries and other devices
US7026071B2 (en) 1996-10-11 2006-04-11 Massachusetts Institute Of Technology Non-crosslinked, amorphous, block copolymer electrolyte for batteries
US6265107B1 (en) * 1996-12-16 2001-07-24 Daikin Industries, Ltd. Binder for rechargeable battery with nonaqueous electrolyte and battery electrode depolarizing mix prepared using the same
US6416902B1 (en) * 1997-04-24 2002-07-09 Fuji Photo Film Co., Ltd. Non-aqueous lithium ion secondary battery
US5766796A (en) * 1997-05-06 1998-06-16 Eic Laboratories, Inc. Passivation-free solid state battery
US6277521B1 (en) 1997-05-15 2001-08-21 Fmc Corporation Lithium metal oxide containing multiple dopants and method of preparing same
US6582852B1 (en) 1997-05-15 2003-06-24 Fmc Corporation Metal oxide containing multiple dopants and method of preparing same
US20040241547A1 (en) * 1997-05-15 2004-12-02 Yuan Gao Metal oxide containing multiple dopants and methods of preparing same
US6794085B2 (en) * 1997-05-15 2004-09-21 Fmc Corporation Metal oxide containing multiple dopants and method of preparing same
US20020197533A1 (en) * 1997-05-15 2002-12-26 Yuan Gao Metal oxide containing multiple dopants and method of preparing same
US6017654A (en) * 1997-08-04 2000-01-25 Carnegie Mellon University Cathode materials for lithium-ion secondary cells
US5900385A (en) * 1997-10-15 1999-05-04 Minnesota Mining And Manufacturing Company Nickel--containing compounds useful as electrodes and method for preparing same
US6078007A (en) * 1998-01-15 2000-06-20 Lidow; Nicholai Hart Selenium photo generator cell with fluid top electrode
US6120565A (en) * 1998-02-12 2000-09-19 Micron Technology, Inc. Method for forming batteries comprising polymeric binder material
US6114061A (en) * 1998-02-12 2000-09-05 Micron Technology, Inc. Battery electrodes, batteries, and methods of forming batteries and battery electrodes
US6136470A (en) * 1998-02-20 2000-10-24 Micron Technology, Inc. Battery electrodes, batteries, and methods of forming batteries and battery electrodes
US6045950A (en) * 1998-06-26 2000-04-04 Duracell Inc. Solvent for electrolytic solutions
US6267943B1 (en) 1998-10-15 2001-07-31 Fmc Corporation Lithium manganese oxide spinel compound and method of preparing same
US6423294B2 (en) 1998-10-15 2002-07-23 Fmc Corporation Lithium manganese oxide spinel compound and method of preparing same
US6517803B2 (en) 1998-10-15 2003-02-11 Fmc Corporation Highly crystalline Mn2O3 or Mn3O4 manganese oxides
US7074382B2 (en) 1998-11-13 2006-07-11 Fmc Corporation Layered lithium metal oxides free of localized cubic spinel-like structural phases and methods of making same
US6620400B2 (en) 1998-11-13 2003-09-16 Fmc Corporation Method of producing layered lithium metal oxides free of localized cubic spinel-like structural phases
US6589499B2 (en) 1998-11-13 2003-07-08 Fmc Corporation Layered lithium cobalt oxides free of localized cubic spinel-like structural phases and method of making same
US6361756B1 (en) 1998-11-20 2002-03-26 Fmc Corporation Doped lithium manganese oxide compounds and methods of preparing same
WO2000063923A1 (en) * 1999-04-16 2000-10-26 Massachusetts Institute Of Technology Layered lithium manganese compounds
US6436574B1 (en) * 1999-04-26 2002-08-20 Nec Corporation Nonaqueous electrolyte secondary battery
US6248477B1 (en) 1999-09-29 2001-06-19 Kerr-Mcgee Chemical Llc Cathode intercalation compositions, production methods and rechargeable lithium batteries containing the same
US6482550B1 (en) * 1999-11-12 2002-11-19 Sanyo Electric Co., Ltd. Non-aqueous secondary battery
US6582854B1 (en) * 1999-12-02 2003-06-24 The Honjo Chemical Corporation Lithium ion secondary battery, cathode active material therefor and production thereof
US6998069B1 (en) * 1999-12-03 2006-02-14 Ferro Gmbh Electrode material for positive electrodes of rechargeable lithium batteries
US6579475B2 (en) 1999-12-10 2003-06-17 Fmc Corporation Lithium cobalt oxides and methods of making same
US6932922B2 (en) 1999-12-10 2005-08-23 Fmc Corporation Lithium cobalt oxides and methods of making same
EP2528147A1 (en) 1999-12-29 2012-11-28 Techelios, LLC Nickel-rich and manganese-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US7258821B2 (en) 1999-12-29 2007-08-21 Agere Systems, Inc. Nickel-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
EP2530767A1 (en) 1999-12-29 2012-12-05 Techelios, LLC Nickel-rich and manganese-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
EP2528146A1 (en) 1999-12-29 2012-11-28 Techelios, LLC Nickel-rich and manganese-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US20030206852A1 (en) * 1999-12-29 2003-11-06 Kimberly-Clark Worldwide, Inc. Nickel-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US6623886B2 (en) 1999-12-29 2003-09-23 Kimberly-Clark Worldwide, Inc. Nickel-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US6350543B2 (en) * 1999-12-29 2002-02-26 Kimberly-Clark Worldwide, Inc. Manganese-rich quaternary metal oxide materials as cathodes for lithium-ion and lithium-ion polymer batteries
US6761997B2 (en) * 2000-03-03 2004-07-13 Nissan Motor Co., Ltd. Positive electrode material and battery for nonaquous electrolyte secondary battery
US6399246B1 (en) 2000-05-05 2002-06-04 Eveready Battery Company, Inc. Latex binder for non-aqueous battery electrodes
US8241791B2 (en) 2001-04-27 2012-08-14 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US7078128B2 (en) 2001-04-27 2006-07-18 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US8685565B2 (en) 2001-04-27 2014-04-01 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US20030027048A1 (en) * 2001-04-27 2003-02-06 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US20060147798A1 (en) * 2001-04-27 2006-07-06 3M Innovative Properties Company Cathode compositions for lithium-ion batteries
US20020177041A1 (en) * 2001-05-25 2002-11-28 Microbatterie Gmbh Method for producing electrode sheets for electrochemical elements
US7157184B2 (en) * 2001-05-25 2007-01-02 Microbatterie Gmbh Method for producing electrode sheets for electrochemical elements
US7887953B2 (en) 2001-07-04 2011-02-15 Panasonic Corporation Positive electrode for alkaline storage battery
US20100092862A1 (en) * 2001-07-04 2010-04-15 Panasonic Corporation Positive electrode for alkaline storage battery
US20030017394A1 (en) * 2001-07-04 2003-01-23 Matsushita Electric Industrial Co., Ltd. And Asahi Glass Company, Limited Positive electrode for alkaline storage battery
US7655355B2 (en) * 2001-07-04 2010-02-02 Panasonic Corporation Positive electrode binder for alkaline storage battery
US7686984B2 (en) * 2001-07-14 2010-03-30 University Court Of The University Of St. Andrews Manganese oxide material for electrochemical cells
US20040214086A1 (en) * 2001-07-14 2004-10-28 Bruce Peter George Electrochemical cells
US7368071B2 (en) 2001-08-07 2008-05-06 3M Innovative Properties Company Cathode compositions for lithium ion batteries
US20060159994A1 (en) * 2001-08-07 2006-07-20 Dahn Jeffrey R Cathode compositions for lithium ion batteries
US7767339B2 (en) * 2001-09-14 2010-08-03 Panasonic Corporation Production method of non-aqueous electrolyte secondary battery
US20050198815A1 (en) * 2001-09-14 2005-09-15 Matsushita Electric Industrial Co., Ltd. Non-aqueous electrolyte secondary battery and production method thereof
US20100203386A1 (en) * 2002-03-22 2010-08-12 Lg Chem, Ltd. Cathode active material for lithium secondary battery
US9023525B2 (en) * 2002-03-22 2015-05-05 Lg Chem, Ltd. Cathode active material for lithium secondary battery
US7235193B2 (en) 2002-04-23 2007-06-26 Lg Chem. Ltd. Complex lithium metal oxides with enhanced cycle life and safety and a process for preparation thereof
WO2003092099A1 (en) * 2002-04-23 2003-11-06 Lg Chem. Ltd. Complex lithium metal oxides with enhanced cycle life and safety and a process for preparation thereof
US20040200998A1 (en) * 2002-04-23 2004-10-14 Hong-Kyu Park Complex lithium metal oxides with enhanced cycle life and safety and a process for preparation thereof
US20040121234A1 (en) * 2002-12-23 2004-06-24 3M Innovative Properties Company Cathode composition for rechargeable lithium battery
US20070015055A1 (en) * 2003-04-09 2007-01-18 Lee Jae H Cathode active material comprising additive for improving overdischarge-performance and lithium secondary battery using the same
US20080020284A1 (en) * 2003-04-30 2008-01-24 Universite De Montreal Polymeric Binder for Fused Salts Electrolytes Based Batteries
WO2004097961A3 (en) * 2003-04-30 2005-07-07 Univ Montreal Polymeric binder for fused salts electrolytes based batteries
US20050112054A1 (en) * 2003-11-26 2005-05-26 3M Innovative Properties Company Solid state synthesis of lithium ion battery cathode material
US7488465B2 (en) 2003-11-26 2009-02-10 3M Innovative Properties Company Solid state synthesis of lithium ion battery cathode material
US7211237B2 (en) 2003-11-26 2007-05-01 3M Innovative Properties Company Solid state synthesis of lithium ion battery cathode material
US20070202407A1 (en) * 2003-11-26 2007-08-30 3M Innovative Properties Company Solid state synthesis of lithium ion battery cathode material
US8883348B2 (en) 2005-07-28 2014-11-11 Panasonic Corporation Electrode for lithium ion secondary battery
US7939201B2 (en) 2005-08-08 2011-05-10 A123 Systems, Inc. Nanoscale ion storage materials including co-existing phases or solid solutions
US8057936B2 (en) 2005-08-08 2011-11-15 A123 Systems, Inc. Nanoscale ion storage materials including co-existing phases or solid solutions
US20110195306A1 (en) * 2005-08-08 2011-08-11 A123 Systems, Inc. Nanoscale ion storage materials including co-existing phases or solid solutions
US8158090B2 (en) 2005-08-08 2012-04-17 A123 Systems, Inc. Amorphous and partially amorphous nanoscale ion storage materials
US20070292747A1 (en) * 2005-08-08 2007-12-20 Yet-Ming Chiang Amorphous and partially amorphous nanoscale ion storage materials
US8617430B2 (en) 2005-08-08 2013-12-31 A123 Systems Llc Amorphous and partially amorphous nanoscale ion storage materials
US8323832B2 (en) 2005-08-08 2012-12-04 A123 Systems, Inc. Nanoscale ion storage materials
US20070190418A1 (en) * 2005-08-08 2007-08-16 A123 Systems, Inc. Nanoscale ion storage materials
US20070031732A1 (en) * 2005-08-08 2007-02-08 A123 Systems, Inc. Nanoscale ion storage materials
WO2007064934A3 (en) * 2005-12-02 2008-05-15 A123 Systems Inc Amorphous and partially amorphous nanoscale ion storage materials
CN102318109A (en) * 2009-02-06 2012-01-11 松下电器产业株式会社 Lithium ion secondary battery and method for producing lithium ion secondary battery
US20110053003A1 (en) * 2009-02-06 2011-03-03 Masaki Deguchi Lithium ion secondary battery and method for producing lithium ion secondary battery
US20110045360A1 (en) * 2009-02-06 2011-02-24 Masaki Deguchi Lithium ion secondary battery and method for producing lithium ion secondary battery
CN101826640B (en) * 2009-03-02 2013-01-02 上海比亚迪有限公司 Pole core for lithium ion battery and lithium ion battery using pole core
EP2624341A4 (en) * 2010-09-30 2015-10-07 Asahi Glass Co Ltd POSITIVE ELECTRODE MATERIAL MIXTURE FOR NONAQUEOUS SECONDARY CELL, AND POSITIVE ELECTRODE FOR NONAQUEOUS SECONDARY CELL AND SECONDARY CELL USING SAME
US9214665B2 (en) 2010-09-30 2015-12-15 Asahi Glass Company, Limited Positive electrode material mixture, and positive electrode for non-aqueous secondary battery and secondary battery, employing it
US9490484B2 (en) 2012-03-28 2016-11-08 Asahi Glass Company, Limited Binder for storage battery device
US10147944B2 (en) 2015-08-04 2018-12-04 Samsung Electronics Co., Ltd. Cathode including sintered polycrystalline material, secondary battery including the cathode, and method of manufacturing the cathode
US11133502B2 (en) 2015-08-04 2021-09-28 Samsung Electronics Co., Ltd. Cathode including sintered polycrystalline material, secondary battery including the cathode, and method of manufacturing the cathode
WO2019219788A1 (en) * 2018-05-17 2019-11-21 Solvay Specialty Polymers Italy S.P.A. Electrode-forming compositions
US11936048B2 (en) 2018-05-17 2024-03-19 Solvay Specialty Polymers Italy S.P.A. Electrode-forming compositions
CN116250100A (en) * 2020-09-30 2023-06-09 松下知识产权经营株式会社 Positive electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery
US11571684B2 (en) * 2020-10-22 2023-02-07 Uchicago Argonne, Llc Lithium ion battery cathode and anode materials as tunable and dynamically responsive support materials for single site heterogeneous catalysis

Similar Documents

Publication Publication Date Title
US5609975A (en) Positive electrode for non-aqueous electrolyte lithium secondary battery and method of manufacturing the same
US8043747B2 (en) Binder resin composition for nonaqueous electrolyte energy device electrode, nonaqueous electrolyte energy device electrode, and nonaqueous electrolyte energy device
US5352548A (en) Secondary battery
EP0964464B1 (en) Binder for rechargeable battery with nonaqueous electrolyte and battery electrode depolarizing mix prepared using the same
US5296319A (en) Non-aqueous electrolyte secondary battery
JP3692965B2 (en) Lithium secondary battery and method for producing positive electrode thereof
US6709788B2 (en) Lithium secondary cell and method of producing lithium nickel metal oxide positive electrode therefor
EP1022797B1 (en) Polymer electrolyte battery and polymer electrolyte
JPH0831408A (en) Positive electrode for non-aqueous electrolyte lithium secondary battery and method for producing the same
JP2001503906A (en) Compound polymer gel electrode
JP4149815B2 (en) Nonionic surfactant-containing electrolyte and lithium ion battery using the same
JPH11195419A (en) Depolarizing mix for nonaqueous battery and nonaqueous battery
JP3540097B2 (en) Electrode mixture for non-aqueous battery and non-aqueous battery
JPH08321326A (en) Lithium secondary battery
JP3067544B2 (en) Positive electrode for lithium secondary battery and method for producing the same
JP3182195B2 (en) Electrode for non-aqueous electrolyte secondary battery and battery using the same
EP0810681B1 (en) Nonaqueous electrolyte secondary battery
Appetecchi et al. Novel types of lithium-ion polymer electrolyte batteries
JP2000067853A (en) Negative electrode for lithium secondary battery
JP3016447B2 (en) Non-aqueous electrolyte battery
KR20000075095A (en) A positive electrode for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery using the same
US20240055599A1 (en) Battery cell and module aging
JPH10188985A (en) Non-aqueous electrolyte secondary battery
JPH07296815A (en) Non-aqueous electrolyte secondary battery
JP2000090970A (en) Lithium secondary battery

Legal Events

Date Code Title Description
AS Assignment

Owner name: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HASEGAWA, MASAKI;BITO, YASUHIKO;ITO, SHUJI;AND OTHERS;REEL/FRAME:007518/0612

Effective date: 19950518

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12